Hydropneumatic plunger-elevator.



L. ATWOOD.

HYDROPNEUMATIG PLUNGER ELEVATOR.

APPLICATION FILED DEC. 23, 1909.

Patented July 9, 1912.

2 SHEETSSHEET l.

L. ATWOOD.

HYDROPNEUMATIG PLUNGER ELEVATOR.

APPLICATION FILED DEC. 23, 1909.

LO3$U40 V Patented July9, 1912.

2 SHEETS-SHEET 2.

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LEONARD .ATWOOD, OF FARMINGTON FALLS, MAINE, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

HYDROPNEUMATIC PLUNGER-ELEVATOR.

Specification of Letters Patent.

' Patented July 9, 1912.

Application filed December 23, 1909. Serial No. 534,709.

To all whom it may concern Be it known that I, LEONARD A'rwooo, a citizen of the United States, residing at Farmington Falls, in the county of Franklin and State of Maine have invented a new and useful Improvement in Hydropneumatic Plunger-Elevators, of which the following is a specification.

My invention relates to improvements in hydro-pneumatic hoisting apparatus, and has for one of its objects the provision of a hoisting apparatus in which air under pressure is'used to do the work of lifting, and water, or other non-compressible liquid, acting upon a piston or plunger arranged to move in a cylinder, is employed to prevent vibration of the car or platform, which would be produced by the direct action of the compressible and elastic fluid upon the same.

Andther object is the provision of a valve apparatus for controlling the flow of both the air and liquid mediums to effect the operation of the hoisting apparatus when raising or lowering a load.

A further object is the provision of a fluid pressure elevator comprising a cylinder which incloses a hollow plunger, a liquid entirely contained in the cylinder and plunger, and an outside source of air pressure for causing the liquid to circulate from the plunger to the cylinder and vice-versa to effect the operation of the plunger and connected car.

Other objects will appear hereinafter, the novel combinations of elements being pointed out in the claims.

In hydraulic hoists it is customary to have a pressure tank and a steam pump to keep it supplied with water, the water from the hydraulic cylinder being discharged into another tank from which the pump transfers it to the pressure tank. In such case it is obvious that the absorption of power is the same whether the load lifted be heavy or light. Furthermore, it is found diflicult, if not impossible, to operate a hoist by the direct action of an elastic compressible fluid such as air, upon the piston or plunger, for the reason that the car tends to vibrate. and to rise suddenly, as if upon springs when the load is removed. These difficulties among others, are overcome by my invention, which I will now describe.

In the accompanying. drawings, Figure 1 illustrates a direct lift or plunger elevator system embodying my invention; Fig. 2 is a sectional view of the plunger and valve mechanism.

Similar reference characters denote similar parts in both figures.

Referring to Fig. 1, B designates a hollow plunger arranged to travel in a cylinder A which is closed at the bottom and provided with a stuffing box at its upper end. Secured to the top of the plunger B is a valve casing D which is bolted to a platen H fastened to the bot-tom of a car C. A cable R is connected at one end to the top of the car C and passes up over guide sheaves S located at the top of the hatchway, and is connected at its other end to" a suitable counter-.

balance weight W. This counter-balance weight W has sufficient weight to counterbalance the plunger and car less preponderance enough to allow the car to descend when empty. An operating lever 19 is located in the car C and is arranged to raise or lower the rod-22 which is connected to the valve apparatus. The lever 19 is provided with a latch 21 arranged to cooperate with a notched quadrant 20. The valve casing D is connected by suitable flexible piping l and 11 to the pipes 12 and 13, which latter are connected to the exhaust and pressure tanks E and P respectively. The pressure tank P is provided with a gage 23 and blow-oil 14, While the exhaust tank E is provided with a vacuum check valve 15. G designates a pump of any suitable character, such as steam or electric, which is connected by the pipes 16 and 17 to the pressure and exhaust tanks P and E respectively. The pump G is arranged to pump air from the exhaust tank E- into the tank P under pressure. The blow-ofl 14 on the tank P prevents the air pressure from rising beyond a certain limit,

while the vacuum valve permit-s air to enter the tank E when the pressure therein falls below that of the atmosphere. The operation of the pump G may be controlled in any desired manner, so as to maintain a substantially constant air pressure in the tank P. Such controlling means is not illus trated on the drawing since it forms no part of the present invention and is well understood by those versed in the art.

Referring to the detail sectional view shown in Fig; 2, 37 is a screw plug which closes the end of the hollow plunger B. A valve 35 closely fits the inside bore of the plunger and is arranged, to normally close a series of ports 36 in the plunger tubing. These ports are preferably arranged spirally so that as the valve 35 is movedin one direction or the other, more or less of the ports are uncovered depending upon the extent of movement of the valve 35. This valve is operated by a valve rod 34 which works in a guide 38 and is connected through an adjustable slip -joint .32to a rod 22. The valve casing D contains a Valve 29 secured to the rod 22 and arranged to normally. close a series of ports-30 and 31 communicating with the inside of the plunger. The rod 22 passes through a stufling box 28 in the platen H and is carried-a short distance-into the" car C. An operating lever 19 is pivoted to a stationary bracket 26 secured to the floor- .of the car. One arm of the lever 19 is provalve 35 completely covers the ports 36 so that thereis no outlet for theliquid contained in the cylinder A, consequently the plunger and connected parts remain in a state of equilibrium being supported by the hydrostatic column of liquid in the cylinder A.

The operation of the apparatus just de scribed is as follows: The operating lever 19' is first moved in a right hand direction thereby effecting a movement of the rod 22 in an upward direction through the slot and pin connection 25 and 24. As the rod 22 sure tank P to .enter the plunger.

' to the plunger before a communication is moves upwardly the valve 29. connected thereto is raised, uncovering the ports 31 and allowing compressed air from the pres- Upon movmg' the rod 22 and valve 29 upwardly, the valve 35 is also raised, but, owing to the lost motion between the rods22 and 34 at the slip joint32, the valve 29 uncdvers the ports 31 before the valve 35 has uncovered the ports'36, consequently compressed.

air from. the pressure tank P is admitted established between the liquid contained in the plunger and that contained in the cylinderv As the valve 35 is raised so as to uncover more or less of the ports 36, the

pressure of air from the tank P forces the liquid in the plunger through the ports 36 and the additional pressure now placed upon the liquid in the cylinder destroys the equilibrium which existed when the ports 36' nected car move upwardly, the liquid circulating from the plunger to the cylinder. The speed of the car will depend to a great extent upon the air pressure and the extent I of movement of the valve 35, this last factor being controlled from the car by means of the lever 19. In order to bring the car and plunger to rest, the controlling lever -19 is I brought back to center, moving the rod22 and valve 29 downwardly, thereby cutting off the supply of compressed air to the plunger. Since the slip joint 32 allows a relative movement between the valves .29 and 35, the valve 29 will move downward a short distance, or until the lost motion in the slip oint is taken up,before the valve 35 will start to move. The valves 29 and 35 are so adjusted to each other that the latter will completely close. the ports 36'at substantially the same time that the valve 29 closes its ports 31. While the closure of either of the valves 29 or 35 would arrest the movement of the plunger, it is desirable to have them close substantially at the same 'were closed and the plunger and its contime, for should-the valve 29 close first, the

liquid upon which the plunger rests would still be in communication with the compressed air entrapped in the upper part of the plunger and the latter would tend to vibrate. By closing the valves together, or by closing the valve 35 shortly in advance of the valve 29 the plunger comes to rest 1 upon a column of liquid, no air cushion being formed. In order to cause the plunger to descend, the operating lever 19 is moved over to the left, causing the valves 29 and 35 to move in a downward direction. The valve 29 will uncover the ports 30 at substantially the same time that the valve 35 uncovers the. ports 36. The unbalanced.

weight ofthe car and plunger now causes the latter to descend into the cylinder the liquid displaced by the plungerfiowmg mto the plunger through the ports 36 andvforcing the air contained in the-upper part of the plunger to escape by way of the ports 30 and pipes 10 and 12 into the exhaust tank The extent of movement of the valve 35 regulates the passage of liquid vfrom the cylinder into the plunger, and therefore the speed of descent of theplunger and car.

Upon centering the operating lever 19 the valve 29 and 35 are entirely closed and the plunger remains stationary, resting on the column of liquid contained in the cylinder A. The slip joint 32 furnishes a s imple means for adjusting the relative P08113101} of the valves 29 and 35 with respect to each other, and by altering the lap of the valves the order of their operation may be varied.

i From the foregoing description it is seen that the valve 35 which controls the ports 36 is opened after the valve 29 has opened. the ports 30 or 31. This arrangement is the compressed air and circulating liquid, it is possible to control the downward movement of the plunger even though one of the valves should become inoperative. Thus the element of danger due to a falling car is en? ing compressed air to the plunger, and

tirely eliminated.

My invention not only secures all the ad--- vantages of quickness of action, economy, etc., which occur from the employment of compressed air, but also the advantages of a hydraulic action upon the car in ascending and descending, thus securing the combined advantages of hydraulic and pneumatic action, while at the same time avoiding the defects which are characteristic of either system alone. The amount of liquid necessary for the properoperation of an elevator embodying my invention is reduced to a minimum, a quantity sufficient to immerse the valve 35 when the plunger is at the top of its stroke being all that is necessary. Furthermore, when the elevator is intended for portable purposes or where it is subjected to extremes of temperature, a cheap grade of oil may be used as a circulating medium.

My invention is not confined to direct acting or plunger elevators but is aqually adapted to all forms of fluid pressure hoisting machinery. The valves controlling the flow of compressed air and liquid may be cylindrical valves as shown, or of any other desired type, such as piston, puppet, or balancedvalves. If desired the exhaust tank E may be dispensed with, the air discharged from the apparatus escaping into the atmosphere. The use of the tank E is recommended however, as by its use the efiiciency of the system as a whole is increased, since the tank E stores up energy in the form of air under pressure every time the elevator car descends, which energy would be lost if the air were allowed to escape.

' I desire not to be. confined or limited to the particular mechanism herein shown, nor to the precise arrangement of parts as set forth, since various changes in the details of the apparatus embodying my invention could readily be made by those skilled in the art withoutmaterially departing from my invention.

What I claim as new, and desire to secure by Letters Patent of the United States is 1. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger closed at top and bottom and arranged to move in said cylinder, a car carried by the plunger, a non-compressible'fluid contained in said cylinder and plunger, means for transmitting the fluid from said cylinder to said plunger and vice-versa, and means for placing said fluid in communication with external fluid pressure.

2. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger closed at top and bottom and arranged to move in said cylinder, a car carried by the plunger, a non-compressible fluid entirely contained in said cylinder and plunger during said movement, means. for supplyvalve mechanism for controlling the flow of air to and from said plunger.

3. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged to move in said cylinder, an elevator car operatively connected to said plunger, a non-compressible fluid contained in said cylinder and plunger, and means operable from the car for controlling the flow of air under pressure to and from said plunger. v

i. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, an elevator car connected to move with said plunger, a non-compressible fluid wholly contained in said cylinder and plunger, a source of air under pressure, and valve mechanism operated from the car for controlling the flow of said fluid and said air.

5. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, a non-compressible fluid wholly contained in said cyl inder and plunger, a valve arranged to control the transmission of said fluid between said plunger and cylinder, an additional valve arranged to controlthe flow of air under pressure to and from said plunger, and a single means for controlling the operation of both of said valves.

6. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, a non-compressible fluid wholly contained in said cylinder and plunger, a valve arranged to control the transmission of said fluid between said cylinder and plunger, an additional valve arranged to control the flow of air under pressure to and from said plunger,

means for operating both of said valves, and

a lost-motion connection between said valves.

7. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, a car operatively connected to said plunger, a noncompressible fluidwholly contained in said cylinder and plunger, a valve arranged to control the transmission of said flu1d between said cylinder and plunger, an additional valve arranged to control the flow of air under pressure to and from said plunger, a lost-motion connection between said valves, and means in the car for eil'ecting the operation of both of said valves.

8. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow air tight plunger arranged for movement therein, a fluid contained in-said cylinder and plunger", a valve for controlling thev flow of said fluid, an additional valve arranged to admit compressed air to'the interior of said plunger and to allow the same to escape therefrom, and means for operating both of said valves one before the other.- e

9. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, ports'in the lower portion of the plunger communicat-- ing with the interior of the cylinder, a valve for controlling said ports, other ports arranged near the upper end of the plunger for conveying air under pressure to and from said plunger, a valve for controlling these latter ports, and an operating device mechanically connecting and controlling.

both of said valves.

10. In a hydro-pneumatic elevator, the combination of a cylinder, a hollow plunger arranged for movement therein, a non-compressible fluid wholly contained in said cylinder and plunger'during such movement, a valve for controlling the transmission of said fluid from said punger to said cylinder and vice-versa, a valve controlling the pressure of air within said .plunger, and an operating device common to both valves.

11. In a hydro-pneumatic elevator, the

combination of a cylinder, a hollow plunger.

arranged for movement therein, an elevator car connected to move with said plunger, a non-compressible fluid wholly contained in said cylinder and plunger, a valve for controlling the passage of fluid from said cylinder and plunger and vice-versa, a valve arranged to vary the pressure of air within said plunger, and means operable from the car for controlling the operation of both of said valves.

12. In a hydro-pneumatic elevator, the combination of a cylinder, an air-tight hol low plunger arr'angedfor movement therem, a non-compressible fluid wholly contained in said cylinder and plunger, ports connecting the interior of the plunger with I the cylinder, a valve arranged to control said-ports, inlet and exhaust ports communieating with the interior of the plunger at its upper end, a valve controlling said inlet and exhaust ports, flexible tubing connecting said inlet and exhaust ports to a pressure and exhaust tank respectively, an air pump connected to each of said tanks, and means for effecting the operation of both of said valves.

In testimony whereof, I have signed my name to this specification in the presence of two subscrlblng witnesses.

Witnesses: I CHAS. C. Conn,

WILLIAM N. FOLLANSBY.

LEONARD ATWooD; 

